The disclosures herein relate in general to electronic circuitry, and in particular to a method and system for converting a direct current (“DC”) voltage.
A conventional voltage mode hysteretic DC/DC buck converter may support a relatively wide range of variability (e.g., capacitance and inductance) in off-chip components, without compromising output voltage ripple. However, while operating in discontinuous conduction mode (“DCM”) under light load conditions (e.g., less than 1 mA), such converter's quiescent current (“IQQ”) loss could unacceptably degrade efficiency (e.g., in a voltage-hysteretic comparator of a DC/DC control loop), especially if such IQQ loss is significant relative to such converter's switching and conduction losses under light load conditions. Moreover, such converter might consume an unacceptably high amount of power.
By comparison, under light load conditions: (a) a constant on time (“COT”) DC/DC converter may have acceptably small IQQ loss, but such converter supports a relatively narrow range of variability in off-chip components; and (b) a current mode hysteretic DC/DC converter may have acceptably small IQQ loss, but such converter might rely on an unacceptably large inductor (e.g., 10 μH+) for accurate current sensing.